1. Field of Invention
The invention relates to a flexible cable harness for use in an image forming apparatus. In particular, the invention relates to a flexible cable harness with a plurality of flexible cables that transmit electrical signals from a main body to a carriage in an image forming apparatus, such as a printer, a facsimile machine, and a copier.
2. Description of Related Art
Conventionally, there exists ink jet image forming apparatuses, such as a printer, a facsimile machine, and a copier, in which a carriage mounted in an ink cartridge thereon reciprocates in a main scanning direction to perform printing on a recording medium. In such an apparatus as shown in FIG. 6, a round guide shaft 211 is disposed between a left side plate 212e and a right side plate 212f, and a carriage 210 is slidingly guided onto the guide shaft 211 to reciprocate in an X direction. The carriage 210 includes a recording head 215 that ejects ink. When the recording head 215 is designed for color printing, it communicates with a control part 200 fixed to a main body of the image forming apparatus to transmit drive signals via four flexible flat cables (hereinafter referred to as flexible cables) FFC1-FFC4.
The flexible cables FFC1-FFC4 are connected to corresponding connectors 201 of the control part 200 at one end and corresponding connectors 203 of the recording head 215 at the other end. The flexible cables FFC1-FFC4 drawn from the connectors 201 are tied in a bundle to a rear frame 212 near the connectors 201 by a binding plate 202 so as to prevent entanglement. The flexible cables FFC1-FFC4 are bent at a curve A and tied in a bundle near the connectors 203 by a binding plate 204.
When the carriage 210 reciprocates in the X direction, the flexible cables FFC1-FFC4 also move while bending more at the curve A. Especially, the flexible cables located more inward at the curve A may suffer more stress. Further, while the adjacent cables rub against each other, they are also subjected to stress. For these reasons, the flexible cables may be prone to damage or breakage at an early stage.
Japanese Laid-Open Patent Publication No. 4-133780 proposes that, as a method for fixing a plurality of flexible cables in a bundle, each flexible cable has the same length between two connectors. Each cable is also provided with its own positioning hole thereon, so as to fit around a protrusion provided on the carriage.
However, as the length between the connectors is the same on each cable, arranging the connectors separately restricts the connector positions, greatly affects the arrangement of other element parts, and affects the size of the apparatus. Further, as the positioning hole is disposed at one place in the direction of the length of each cable, the conventional problem in that the length between two points to fix each flexible cable by adjusting the position of each cable is not solved.